“Do you know how, once you learn something you start seeing it everywhere?”

No joke, my friend in Kingston, New York said this to me as I was snapping a photo from her roof, of a tree I kept seeing all day, the catalpa, which is plentiful in that part of the Hudson valley.

A catalpa tree in bloom, Rosendale, NY.

From a distance catalpas have the same pale green and fifty feet height of other trees, but as you get closer you realize the leaves are giant, heart-shaped and up to a foot long. Stan Tekiela’s Trees of New York Field Guide says the catalpa, or catawba, is native to the lower Mississippi valley but took to New York when it was planted here for decoration.

Sometimes called the Cigar Tree or Indian bean tree, it’s distinct for the long pods it grows later in summer, like enormous string beans. It makes sense that a catalpa would blossom a month or so later than oaks and maples, since it’s used to Alabama or Mississippi, where summer comes about a month earlier than here. And since this is the week they’re in bloom here, you can see in plain view how many there are.

Catalpas look a lot like those of another tree called the Paulownia or princess tree, except the princess tree’s fruit isn’t a bean-like pod, but clusters of wooded pods that look like almonds. A native of Asia, guides sometimes call princess trees “invasive,” since they grow tenaciously in urban places.

Like the new discipline of permaculture, and like the poet Stephen Dunn, I hear the phrase “invasive species” with caution. “Bad plants? Nature would say, Careful now, watch your language, let’s just see what survives,” Dunn writes.

A princess tree in an auto body shop: “Foreign & Dometic.”

Princess trees were brought from Asia because they grow fast and look pretty, and it’s true they’re invading Gowanus, the neighborhood of Brooklyn where I work. Famous for the polluted canal that sits in its midst, Gowanus is now a dining and bar crawl destination, but still a good place to get a flat tire fixed.

This winter I could see clusters of princess trees’ fruit while the branches were bare. This month I got to see them bloom: The Royal Horticultural Society says another name for them is foxglove trees, since their blossoms look like the flower. Now the flowers are almost gone and the fruit regenerating.

Is the catalpa’s “invasion” less of an affront to our Yankee ecosystem since it came from Memphis, while the princess upsets our order since it came all the way from central China?